1. Field of the Invention:
The present invention relates to an hydraulic separating device with an automatic flow control, and more particularly to such a device for separating particulate matter from a carrier fluid, the device effectively performing such separation over a relatively wide range of fluid flow rates while minimizing the pressure drop in fluid passing through the device at higher flow rates.
2. Background of the Invention
The prior art includes a variety of cyclonic or vortexing separating devices. Such devices separate particulate matter from a carrier fluid by inducing movement of the fluid and particulate matter in a swirling path within a vortexing chamber. The swirling path is typically induced in a cylindrical chamber by positioning a fluid inlet in tangential relation thereto. The particulate matter is displaced outwardly within the vortexing chamber by centrifugal force and then descends from the main body of the fluid. Since the centrifugal forces developed by the swirling fluid vary with the rotational velocity, it can be seen that at low rotational velocities the particulate matter is not effectively thrown outwardly but passes through the separator with the main body of the carrier fluid.
This failure of separation at low rotational velocities causes great difficulties in the provision of practical cyclonic separators since each conformation of conventional separators is only adapted to a relatively narrow range of flow rates. At flow rates below this narrow range, separation of the particulate matter is unsatisfactory. At higher flow rates, while separation may be achieved, extremely high pressure drops occur with resulting waste of the energy required to pump or draw the fluid through the separator. Also, at higher flow rates rapid wear occurs to elements of the separator exposed to the rapidly swirling particulate matter which is often sand or some other abrasive material.
Because of the narrow range of flow rates for which a single conventional cyclonic separator is suitable, it has not heretofore been possible to provide a separator which is satisfactory for use with fluid systems having a wide range of flow rates. With such systems, either or both of the extremes of insufficient separation and excessive pressure drop have been present. Systems having intermittent fluid flow also present difficulties. Although full flow may be within the range of a separator, some period of time is required for the velocity to build up each time the flow is initiated resulting in poor or no separation during such periods. Even if all fluid systems had a steady flow rate there would be an ecconomic penalty because of the narrow range of a given separator configuration. This is because a wide range of separator configurations is required to handle the wide range of flow rates found in practice with the attendant manufacturing and inventory costs necessary to provide these configurations.
Various forms of cyclonic separators have been proposed to overcome or minimize the limited range of flow rates which effectively can be handled by a single cyclonic separator configuration. One such successful form is disclosed in my U.S. Pat. No. 3,568,837. However, even this form of separator is subject to certain difficulties which the present invention has overcome.